Electronic devices that utilize integrated circuits are susceptible to electrostatic discharges (ESDs). An electrostatic discharge may occur from a human holding the device or other source. An electrostatic discharge can pass a large amount of electric current through circuitry that is sensitive to such high currents, thus damaging the circuitry. To reduce the susceptibility to ESD damage, integrated circuits typically include an ESD device that channels ESDs away from sensitive circuitry.
One type of ESD device involves multiple active regions, such as source or drain regions, between an elongated gate device. The gate device is used for the gate of a transistor. The transistor acts as a switch that opens when a high electric current such as an ESD is detected. The open switch allows the ESD passes through in order to avoid flowing through the sensitive circuitry.
One issue involved in forming an ESD device comes from silicide. When forming transistor devices, a silicide material is commonly used at semiconductor-metal junctions to facilitate an efficient junction. This is because silicide conducts electric current relatively well. However, it is desirable that the silicide is not formed over the source or drain regions adjacent to the gate. If silicide layers were to be formed there, the current flowing through the source and drain regions would tend to travel mostly through the silicide, which may cause damage because the current density resulting from the high ESD currents may burn away the silicide and surrounding material.
Another issue involving the formation of ESD devices arises when the source drain regions are formed through an epitaxial growth process. An epitaxial growth process involves growing a semiconductor crystal onto an existing crystal. When forming source or drain regions in such a manner, the length of the regions can affect the uniformity of the epitaxial grown structures. If a structure is too long compared to other nearby structures, a set of non-uniform epitaxially grown structures may be formed. This is referred to as the loading effect. It is thus desirable to fabricate ESD devices, or other devices that utilize epitaxially grown active regions between gates, without too much of an adverse loading effect.